The present invention relates to a hollow carbon fiber, a hollow carbon particle, a production method thereof, and composite of the fiber and resin.
The hollow carbon fiber represented by a carbon nano-tube is several nm to several hundred nm in diameter and several nm to several dozen nm in length, and the wall thereof is cylindrical in form and is made of several to several dozen graphite walls (layers).
Such a hollow carbon fiber has attracted attention for such conspicuous characteristics as mechanical strength, hydrogen storage properties and electric field discharge properties, and studies have been made on its practical application.
Japanese Patent No. 2845675 discloses a method in which carbon is coagulated subsequent to its evaporation by arc discharge in an inactive atmosphere; Japanese Application Patent Laid-Open Publication NO.109310/2000 discloses a method in which at least one of X-rays, microwaves and ultrasonic waves are applied to carbon material including —C° C— and/or —C═C—; and Japanese Application Patent Laid-Open Publication NO. 95509/2000 discloses a method wherein a carbon nano-tube is made to grow by contact between carbon vapor and a non-magnetic transition metal.
In any of these production methods, however, the yield of the intended carbon nano-tube is low, and the by-product of carbonaceous material similar to carbon black and amorphous carbon cannot be avoided. When a metallic catalyst is used, it is necessary to refine the reaction products, and a metallic catalyst cannot be removed completely by refining, with the result that the aforementioned hydrogen storage properties and electric field discharge properties are reduced. Such disadvantages cannot be avoided in the prior art.
Further, the aforementioned production methods are practically incapable of controlling the number of wall layers, the diameter and the length of the hollow carbon tube represented by a carbon nano-tube. It has been very difficult to attain a uniform shape and uniform characteristics.
A hollow carbon particle represented by fullerene is several nm to several hundred nm in diameter, and the wall comprises several nm to several dozen graphite layers, including a five-membered ring or seven-membered ring.
Hollow carbon particles have attracted attention for such conspicuous characteristics as mechanical strength, hydrogen storage properties and electric field discharge properties, and studies have been made on its practical application. In the conventional method of its production, carbon is coagulated subsequent to its evaporation by arc discharge in an inactive atmosphere, and it is then separated and refined.
However, the yield of fullerene is low, and the by-product of carbonaceous material similar to carbon black and amorphous carbon cannot be avoided. Further, separation and refining using a solvent, such as benzene, are essential, and a remarkable reduction in productivity has been unavoidable.
Further, the aforementioned production methods are practically incapable of controlling the number of wall layers, the diameter and the length of the hollow carbon particles represented by fullerene.